'Abdullah bin 'Amro bin al-As (RAA) narrated that the Messenger of Allah (ﷺ) said:

“For a man to insult his parents, is one of the major sins.” It was asked, ‘Does a man insult his parents?’ He replied “Yes, he insults the father of a man who in return insults his father, and he insults a man’s mother who in return insult his.” Agreed upon.

وَعَنْ عَبْدِ اَللَّهِ بْنِ عَمْرِو بْنِ الْعَاصِ ‏-رَضِيَ اَللَّهُ عَنْهُمَا‏- أَنَّ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-قَالَ: { مِنْ اَلْكَبَائِرِ شَتْمُ اَلرَّجُلِ وَالِدَيْهِ.‏ قِيلَ: وَهَلْ يَسُبُّ اَلرَّجُلُ وَالِدَيْهِ? قَالَ: نَعَمْ.‏ يَسُبُّ أَبَا اَلرَّجُلِ, فَيَسُبُّ أَبَاهُ, وَيَسُبُّ أُمَّهُ, فَيَسُبُّ أُمَّهُ } مُتَّفَقٌ عَلَيْهِ .‏ [1]‏ .‏